Method for producing earth boreholes

ABSTRACT

In a method for producing and widening ground bores or for the destructive replacement of buried lines with the aid of a tool arranged at the end of a rod driven by a boring device, the rod is built up from individual sections which are to be connected to one another in a machine excavation (staring excavation). In order to allow the use even of rod sections whose length is equal or almost equal to the diameter of the machine excavation, the boring device, prior to the introduction of a new rod section, is displaced, for example inclined, in such a manner that the rod section can be slid into the boring device, for example from outside the excavation, without interference from the rear end, projecting into the machine excavation, of a rod section which has already been introduced into the ground. As soon as the rod section has been slid in, the boring device together with the rod section is moved into a position in which it is aligned with the boring direction or the rod part which is already in the ground.

The invention relates to a method for producing and widening groundbores or for the destructive replacement of lines which have been laidin the ground, and invokes the priorities of German patent applications101 34 036.2 and 101 59 712.6-24, to the content of which reference ismade.

Methods of this type generally use a boring device which is suitable forhorizontal boring and has a rod, at the free end of which a tool issuitable for boring and/or widening in the ground or for destroying anold pipe which has been laid in the ground. The rod comprises individualsections which are screwed together or are fitted and screwed to therear end of the rod part which is already in the ground. However, thisfitting and screwing operation encounters difficulties, since the boringdevice must be located at the level of the ground bore or of the oldpipe and accordingly is usually arranged in a starting excavation, i.e.in an excavation which has previously been dug or in an existing manholeof a sewerage system.

The total length of the rod section and of the boring device maycorrespond to at most the diameter of the manhole or of the manholeopening, so that there is still space behind the boring device for a rodsection to be pushed axially into the boring device in order for a newrod section to be connected to the rod part which is already in theground, after which operation of the boring device recommences in orderto introduce the rod section which has been fitted. Given a distance ofup to 60 m between the manholes and a standard manhole diameter of 100to 120 cm, and at most 160 cm, this means that introducing a rod sectionover the entire distance entails a considerable outlay on time.

Moreover, on account of the shortness of the rod sections, a largenumber of—for example 60 or 70—expensive socket or screw connectionswhich are susceptible to faults are required. An additional factor isthat with pneumatically driven boring devices there are startingdifficulties if the length of hose running from a compressor to theboring device exceeds a certain level.

The abovementioned problems occur both if a new ground bore is producedbetween manholes and a new pipeline is introduced and if an old pipelinewhich is destroyed by a cutting tool on the rod in order for a newpipeline subsequently to be introduced is present between the manholes.

In the case of boring with a boring device arranged in an excavationwhich has been dug, the same difficulties arise if the excavation is ofapproximately the same width as a standard manhole; they can beeliminated or alleviated if the clear width is (considerably) larger.However, this requires a correspondingly increased amount of earth to beexcavated and therefore entails increased costs. Moreover, it presentsproblems on account of the need to temporarily store or transport awaythe soil which has been excavated.

The journal “s+t46 (1992)11”, pages 10, 12, 14, has also alreadydisclosed a method for the trench-free laying of supply lines in whichfirst of all two excavations, i.e. a starting excavation and a targetexcavation, are dug. Then, a boring device which is located above theground and works obliquely creates an inclined bore with respect to thestarting excavation and then a substantially horizontal bore leading tothe target excavation. Then, the boring rod is provided in the targetexcavation with a widening head which works in the opposite directionand is finally pulled back until it reaches the starting excavation.

However, it is often not acceptable or highly complex to produce anauxiliary bore, requiring subsequent closure of the auxiliary bore andrestoration of the hole wall and of the surrounding surface finish (roadsurfacing, forecourt plants, etc.).

Therefore, the invention is based on the problem of avoiding thedrawbacks which result from the limited length of the rod sections orthe need to dig out an excavation with a diameter which is suitable forlonger rod sections or to produce and then eliminate an auxiliary bore.

To avoid these drawbacks, the invention proposes a method in which thecomponent which receives the rod sections (i.e. the rod receiving part)or the entire boring device is first of all moved into a spatialposition which allows the rod sections to be introduced into the rodreceiving part without being impeded by the rear end, projecting intothe machine excavation, of a rod section which has already beenintroduced into the ground. As soon as this has taken place, the rodreceiving part or the boring device is moved back into the boringposition, i.e. flush with the bore or that part of the rod which isalready in the ground, where it is connected to the last rod section ofthe rod part which is already in the ground.

In the present context, the term rod receiving part is to be understoodas meaning that part of a boring device which on one side is connectedto the boring drive and on the other side receives the rear end of a rodsection before this rod section is connected to the previous rodsection. A rod receiving part of this type, in the form of a plugcoupling, is described in German patent 197 25 628 and the correspondingU.S. Pat. No. 6,267,187.

To introduce a rod section, it is sufficient for the receiving part forthe rod section, for example a coupling on the rotary drive for the rod,to be moved out of its boring position, for example to be displacedupward.

The change in position of a standard boring device can also be effectedby pivoting between the boring position and the receiving position.Another possible option consists in moving the receiving part for therod sections or the boring device between the two positions with the aidof a raising carriage or a type of lifting platform, which enable therod sections to be introduced into the device above the boring level,for example at ground level.

In the case of pivoting, it is possible to use a boring device which isprovided with at least one pivot bearing at the front or the rear, asseen in the boring direction. A device of this type may comprise a basicframe and a mounting which is arranged pivotably thereon and includesthe actual boring device. In this case, a pivot drive, for example ahydraulic or pneumatic cylinder, is located between the basic frame andthe mounting. Furthermore, the basic frame and the mounting may beprovided with a locking mechanism which secures the boring device so asto prevent undesired movements during boring.

However, the basic frame may also serve as a lifting platform or bearranged on a lifting platform, by means of which the device is movedout of the boring position of variable height to the ground level, inorder for a new rod section to be pushed in at that level or—in a targetexcavation—to be removed.

Use of the apparatus according to the invention results in the advantagethat the pipe sections, in order to be pushed into the boring device orto be removed, do not require any additional space in an existingmanhole or in a starting excavation which has been dug out; therefore,they may have a length which corresponds to the hole diameter or to thelength of the boring device. On the other hand, when the apparatusaccording to the invention is used, there is no need for the dimensionof the machine excavation in the horizontal direction to be any greaterthan approximately the length of the boring device.

The invention is explained in more detail below with reference to twoexemplary embodiments. In the drawing:

FIG. 1 shows a boring device according to the invention in its boringposition in an existing manhole,

FIG. 2 shows the device shown in FIG. 1 in its receiving position,

FIG. 3 shows a boring device arranged pivotably on a raising carriage inthree different height positions,

FIG. 4 shows a boring device on a lifting platform in its boringposition, and

FIG. 5 shows a boring device shown in FIG. 3 in its receiving positionabove ground, and

FIG. 6 shows a boring device, the rotary drive of which is verticallydisplaceable.

In a standard manhole 1 (machine excavation/target excavation) with anarrowed opening 2, there is a platform 3 on supports 4 bearing a boringdevice 5. The boring device comprises a basic frame 6, which isconnected, via a pivot bearing 7, to a mounting 8, on which an advancingdrive 9 and a rotary drive 10 are positioned. The advancing drive mayalso be arranged on the basic frame 6. The rotary drive 10 has a hollowshaft (not shown) which is such that it is able to receive a pipesection 11, the front end 12 of which can be screwed to the last rodsection 13 of that part of the rod which is already in the ground. Toallow this to occur, a clamping device 14 for holding the rod section 13in place is located on the mounting 8. Force is transmitted between thehollow shaft and the rod section 11 by means of a positive lock orfrictional lock.

As soon as the rod section 11 has been screwed to the rod section 13,the advancing drive 9 forces the rod 11, 13 into the ground until therear end of the rod section 11 is in the situation of the rod section 13and the mounting 8 has been “emptied”. Then, the mounting 8 is pivotedout of the boring position illustrated in FIG. 1 into the receivingposition illustrated in FIG. 2. This is preferably effected with the aidof a hydraulic cylinder 15 extending between the basic frame of themounting until the mounting 8 has adopted a position in which theextension of the hollow shaft axis 16 extends within the opening 2 ofthe manhole 1. In this position, it is readily possible for a rodsection 11 with a length of approximately the whole diameter to beintroduced into the hollow shaft until it has reached the positionillustrated in FIG. 2. Then, the mounting together with the new rodsection can readily be pivoted back out of this position into the boringposition illustrated in FIG. 1.

In the exemplary embodiment shown in FIG. 3, the boring device 5 isarranged on a raising carriage 17. The raising carriage can be displacedin a framework 18 arranged in the manhole 1 and is connected to apivoting drive (not shown), for example a hydraulic cylinder, whichallows the boring device to be arranged in an inclined position. In thisway, it is possible to move a boring device through the narrowed holeopening 2 in the inclined position and thereby to move it into anabove-ground receiving position, even if its length is greater than theclear width of the hole opening 2. As soon as the boring device 5 hasreached its upper position in FIG. 3, it is pivoted back into ahorizontal position in order to receive a rod section.

The boring device 5 shown in FIGS. 4 and 5, which is used in a dug-outmachine or starting excavation 19, is situated on a lifting platform 20which can be displaced, between supports 21, between the boring position(FIG. 4) and the receiving position above ground.

In the case of the boring device illustrated in FIG. 6, the rotary drive10 is connected to a raising drive 22, which allows the rotary drivetogether with its receiving part 23 for the rear end of a rod section 11to be displaced out of the boring position, in which it is aligned withthe rod section 13 which is already in the ground, upwards into theposition illustrated. In this position, it is possible for rod section11 which is longer than the distance between the rotary drive 10 and therear end of the rod section 14 which is already in the ground to beintroduced into the receiving part 23.

1. A method for producing and widening ground bores or for thedestructive replacement of buried pipelines with the aid of a boringdevice which is arranged in a starting excavation and has a boring rodcomprising a plurality of sections, characterized by moving not all theboring device, but rather the rotary drive for the advancement or atleast part thereof which includes the receiving part for the rodsections, out of its boring position in the starting excavation,introducing or removing a rod section by moving at least the rotarydrive with a rod receiving part out of its boring position at thestarting excavation into a position which allows a rod section to beintroduced into the rod receiving part from outside the startingexcavation, and moving the rotary drive for the advancement or at leasta part thereof which includes the receiving part for the rod sectionsback into the boring position after a rod section has been introduced orremoved.
 2. The method as claimed in claim 1, characterized by raising arod receiving part of the boring device.
 3. The method as claimed inclaim 1, characterized by pivoting the boring device in the startingexcavation into an inclined position about a rotation point located atthe front or the rear.
 4. The method as claimed in claim 1,characterized by moving the receiving part of the boring device for arod section upward.
 5. The method as claimed in claim 4, characterizedby moving a rod receiving part of the boring device for a rod sectionupward.
 6. The method as claimed in claim 1, characterized by pivotingthe boring device out of its boring position into a receiving positionin the starting excavation.
 7. The method as claimed in claim 6,characterized by moving the boring device out of its receiving positionin the starting excavation into a receiving or removal position outsidethe starting excavation and above ground.